Re: [PATCHv1 dont apply] RFC: kvm eoi PV using shared memory

Michael S. Tsirkin
2012-04-16T19:01:18Z

On Mon, Apr 16, 2012 at 08:51:16PM +0300, Gleb Natapov wrote:
> > > Only when eoi is pending. This is rare.
> >
> > This is exactly while guest handles an interrupt.
> > It's not all that rare at all: e.g. device
> > drivers cause an exit from interrupt
> > handler by doing io.
> So eoi will be coalesced with io that device driver does. Exactly what
> we want.

It won't. While we handle interrupts eoi is still set.
So there will be a couple of tests + read from userspace
Wasted not a huge overhead but it's the principle of the thing.

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MST